The goal of this Mentored Patient-Oriented Research Career Award (K23) is to prepare Dr. Heather Niemeier to become an independent scientist studying innovative behavioral approaches for the treatment of obesity. Through a combination of didactic and direct mentored training experiences, this training plan will provide her with skills in the following areas: the etiology and pathophysiology of obesity and the behavioral approach to weight regulation; methodology, statistics, and ethics of clinical research in obesity; and strategies being used to address affective and cognitive factors in eating disorders and addictive disorders and their translation into obesity treatment. Dr. Niemeier will work closely with her mentor, Dr. Rena Wing, and her co-mentors, Drs. Kittichai Promrat, Joseph Fava, Richard Brown, and Carlos Grilo throughout the course of the award. The resources at The Miriam Hospital/Brown Medical School combined with the mentoring by an expert advisory team will provide Dr. Niemeier with the ideal environment to achieve her long-term goals. Obesity is a major public health problem. Behavioral weight loss, the current treatment of choice for moderate obesity, achieves impressive short term results, however, weight regain following treatment is a major problem. Over 50% of participants in behavioral weight loss programs report difficulty with internal antecedents to unhealthy weight control behaviors and this difficulty is associated with weight regain following treatment. Current treatment approaches do not adequately address these antecedents. The aim of this application is to develop, implement, and evaluate a behavioral weight loss program modified to provide participants with skills to deal effectively with affective and cognitive difficulties. Two studies are proposed, both targeting men and women with BMI of 27-40 who self-report difficulty with emotional and/or cognitive antecedents to unhealthy weight control behaviors. Study I is an uncontrolled pilot study in 20 participants to initially assess acceptability and efficacy of the innovative treatment. In study II, 120 participants will be randomly assigned to receive 12 months of standard behavioral therapy for weight loss or standard behavioral treatment plus affective and cognitive skills training. The long-term goal of this research is to improve the weight loss maintenance outcomes of behavioral weight loss programs by addressing affective and cognitive antecedents to unhealthy weight control behaviors.